Climate control systems in automobiles are well known and typically include one or more devices such as a heater, air conditioner, and windshield defroster, and a plurality of pneumatic pathways or passages for delivering conditioned air into the passenger compartment. As used herein, "conditioned air" refers to air that deliberately has been treated for purposes of obtaining or maintaining a desired climate in the automobile, and can include heating, cooling, or the introduction of outside ambient air into the passenger compartment. For example, depending upon which pneumatic passage is used, conditioned air can be directed towards the compartment floor, at mid-level of the compartment, against the windshield, or various combinations thereof.
Controlling the flow of air through such pneumatic passages to a desired output typically is accomplished by means of adjustable doors or baffles. The doors or baffles are adjusted in response to actuators that conventionally are controlled by manual slide lever activators or electrical solenoids. Such actuators are objectionable because they are noisy, often difficult to operate, and do not always effect an efficient coupling of the pneumatic source to the selected door or baffle.
Electrical motors are more desirable, because they are quiet, consistent and reliable. Unfortunately, such motors are also relatively expensive, particularly when many such motors must be provided in a single system. Vacuum motors normally are less expensive, but tend to be noisier, less reliable, and often do not provide the user with control mechanisms that have consistent operating feel and performance.
A need exists for a pneumatic door or baffle control apparatus for use in an automobile climate control system that offers the relative economy of vacuum driven motors and the relative quiet and reliability of electrical motors. An object of this invention is to fulfill such need.